"And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven." Genesis 1:20.
God's creation of life in the waters normally brings to mind the fish, frogs, jellyfish, and other common water animals. But, within aquatic environments of the earth is an animal that most people will never see and have never heard of - the Bear of the Moss or Water Bear. This little-heard-of creature is among some of the amazing animals in God's creation.
The phylum Tardigrade has almost one thousand little-known and mostly microscopic organisms in it. These animals are invertebrates. The largest are just barely visible to the naked eye being about the size of the dot made by a fine lead pencil. They look like miniature caterpillars and have five body segments and four pairs of clawed legs. They have many organ systems like larger animals but lack respiratory and circulatory systems. They breathe through their skin, and their whole bodies work to pump fluids throughout their bodies.
The word tardigrade means "slow walker," which is a good description of their movements. They have sluggish, clumsy movements as they crawl around on the bottom sediment of their water home, living in decomposing materials on the bottom of bodies of both salt and freshwater, on water trapped in mosses and lichens, and even in deserts under special conditions. They must have water to find food, breathe, and to reproduce but are able to survive for long times when water is not available. This ability to survive extreme environmental swings is of special interest to scientists today.
When conditions of low oxygen supply occur in the water, tardigrades have been given a neat "trick" by God called anoxybiosis. Most normal people have never heard of anoxybiosis which is, indeed, an amazing ability. When flooding occurs for bears of the moss and oxygen levels drop below tolerable levels, the tardigrades swell up like little balloons. This inflating allows them to float around at the top of the levels of water where more oxygen will be available by diffusion with the air. They can float around like this for several days as they wait for the water levels to drop back down to normal levels and they find another home among the mosses and lichens or at the bottom of the stream. They then shrink back down to normal and feed growing and reproducing. God has given the tardigrades this amazing survival feature, but that is not the only condition they can survive.
They also exhibit "cryptobiosis." Cryptobiosis occurs when the environment conditions are just the opposite of too much water when it is too dry. If the stream, pond, puddle, moss, lichen, or other home for the tardigrades dries up, then the tardigrades can go into a "reversible state of metabolic suspension," which is sort of a suspended animation. They dry up and shrivel into a wrinkled shape called a "tun," which is about one-third their former sizes. In cryptobiosis, they can survive for long periods of time without food or water. They can enter this condition and return to normal in a matter of just a few hours. Tardigrades have shown that they can survive very cold conditions down to -272.95C for up to twenty hours. They have survived at 120C at 1000 atmospheres and in high vacuums. In this cryptobiotic state, they have shown resistance to hydrogen sulfide, ultraviolet light, and even X-rays. One could think that these organisms could travel unprotected through space without any ill effects. Some tardigrades have been kept alive for more than 100 years by going in and out of this condition.
The "bears of the moss" or "water bears" are among the most unknown of God's creatures and, yet, have some of the most unusual features of any animal on the planet earth. Let us marvel and praise the Creator for the microscopic things we have never seen in the world around us. Rt. 1 Box 116A, Belington, WV 26250. firstname.lastname@example.org
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